In the above technical field, patent literature 1 discloses a technique of reducing wind noise by separating an input acoustic signal into low, middle, and high bands. In patent literature 1, a restored signal in the low band is generated from a middle-band component, a modified acoustic signal for the low band is generated by weighted sum of the restored signal and the original low-band signal, and a modified acoustic signal for the middle band is generated by reducing the signal level of the middle-band component. Lastly, the original high-band signal and each of the modified acoustic signals for the low and middle bands are combined to generate an enhanced signal.
Patent literature 2 discloses a technique of separating an input sound into low and high bands, and suppressing wind noise included in a low-band noisy speech signal in accordance with the probability of wind noise.